Volumetric dispenser



Feb. 1, 1955 J. BUCHLER VOLUMETRIC DISPENSER Filed April 5. 1954 JOSEPH BUN/l R .INVENTOR.

AGENT United States PatentO VOLUMETRIC DISPENSER Joseph Buchler, New York, N. Y. Application April 5, 1954, Serial No. 420,951

5 Claims. (Cl. 222-152) My present invention relates to volumetric devices for dispensing liquids in measured quantities.

It is necessary in such devices, for the purpose of withdrawing part or all of the liquid from the storage vessel containing same, to establish communication between such vessel and the surrounding atmosphere. In cases where direct contact between the liquid and the atmospheric air could result in objectionable contamination, it has heretofore been necessary to provide means for filtering or washing the entering air. This is not entirely satisfactory, since the filters require frequent replacement and, besides, do not insure effective sealing of the liquid against air so as to preclude unwanted oxidation; also, the filtering or washing agents themselves, such as calcium chloride, may have an undesirable affinity to the liquid to be protected, thereby resulting in an adulterated product. Attempts to avoid these drawbacks have hitherto led to unwieldy and complicated arrangements.

The general object of my present invention is to provide simple means for effectively separating a liquid in a dispenser from the atmospheric air while enabling free pressure equalization therebetween.

More specifically, it is an object of my invention to provide a pressure equalization path between a liquid in a storage chamber and a surrounding medium (generally the atmosphere) containing both a protective gas and a protective liquid, the stored liquid being in contact only with the protective gas which in turn is prevented by the protective liquid from mixing with the surrounding medium.

A feature of my present invention resides in the provision, as part of the aforementioned pressure equalization path, of a pair of intercommunicating vessels or chambers inserted in cascade and at different elevations between the storage chamber and the atmosphere, the lower one of these vessels having a connection near its top to the storage chamber as well as a connection near its bottom to the other vessel, whereby the protective gas in this lower vessel will be driven by the weight of the superjacent protective liquid toward the storage chamber whenever any of the liquid stored therein is withdrawn.

A preferred arrangement of a device according to my invention comprises three superposed chambers of which the lowermost, the intermediate and the uppermost ones initially contain, respectively, the stored liquid, the protective gas and the protective liquid; the top chamber is connected to the intermediate chamber by way of a riser tube terminating, as in a siphon bottle, short of the bottom of the latter.

The invention is particularly (though not exclusively) applicable to a volumetric dispenser of the type disclosed in U. S. Patent No. 2,089,796, issued August 10, 1937, to Otto Hopf et al.

Reference is now made to the accompanying drawing for a detailed description of a representative embodiment of my invention (Fig. '1) and a modification (Fig. 2).

In Fig. 1 there is shown at the storage vessel of my improved volumetric dispenser, containing a liquid 11. The vessel 10 terminates at the bottom in a tube 12 leading to the housing 13 of a three-way valve 14 which also connects with a graduated burette 15. Valve 14 is provided with a channel 16 for connecting burette and tube 12 with each other or either of them with a discharge tip 17. The upper extremity of burette 15 is formed into a nozzle 18 opening into an overflow chamber 19 whence a conduit 20, having a constriction 21,

r 2,701,079 Patented Feb. 1, 1 955 returns excess liquid to the neck 22 of vessel 10. A plug 23 in an opening 32 near the top of vessel 10 enables introduction of the liquid 11.

The arrangement so far described corresponds in substance to the apparatus disclosed in aforementioned U. S. Patent No. 2,089,796 and is not claimed per se as my invention.

A second vessel 24, having a closed bottom and an open neck 25 at the top, sits upon neck 22 of vessel 10 and communicates therewith by way of a conduit 26 opening into its own neck 25. The latter supports a third vessel 27 which has a top opening 33 receiving a rotatable vent plug 28 and terminates at its bottom in a riser tube 29.; this tube extends into vessel 24 and ends just above the bottom of that vessel. Vessel 24 is provided near its top with a stopcock 34 leading into the atmosphere.

A protective liquid 30 fills a large portion of vessel 27 as well as tube 29 and part of vessel 24.- Between the two liquids 11, 30 the apparatus is filled with an inert, protective gas 31, such as nitrogen or carbon dioxide. The liquid 30 might be distilled water.

To fill the apparatus, plugs 23 and 28 are removed and the solution 11 is introduced into the vessel 10 and the tube 12 by way of entrance opening 32. Next, liquid 30 is admitted into vessel 24 through the opening 33 and the tube 29. When vessel 24 has been filled with liquid, protective gas 31 is introduced through tip 17 and, with plug 23 reinserted and stopcock 34 opened, will flush the air out of conduits 20, 26 and vessels 10, 24. For this operation, the valve 14 is placed first in one and then in the other of its two remaining operative positions to let the gas rise through burette 15 and then bubble up through liquid 11, or vice versa. After the system has been thoroughly scavenged, stopcock 34 is closed again and the pressure of the gas entering at tip 17 will drive the liquid 30 through riser tube 29 into the upper vessel 27, thus producing the situation shown in the drawing. Valve 14 may now be restored to the position illustrated, thereby enabling the solution 11 to fill the burette 15. Thereafter, plug 28 may be reapplied and placed in its open position as shown, whereupon valve 14 may again be reset for withdrawing a desired amount of solution from burette 15 through tip 17, such withdrawal being accompanied by a drop in the level of liquid 30 within vessel 27 and a corresponding rise in the level of that liquid within vessel 24.

Plug 28 is preferably maintained closed. during storage.

It will be seen from the foregoing description that all conduits between valve 14 and vessel 27 will be occupied at all times either by liquid or by gas 31.

If desired, the entire apparatus may be flushed through with inert gas 31 before vessel 10 is filled with solution 11.

In the modification of Fig. 2, the intermediate vessel 124 is provided with a standard-taper male joint 122a seated in a female joint formed by the neck 122b of lower vessel 110. Conduit 120, corresponding to conduit 20 in Fig. 1, terminates at neck 122b, whereas conduit 126, corresponding to conduit 26 of Fig. 1, opens into joint 122a. It will be understood that the remaining elements of the device of Fig. 2, which have not been i lluls trated, are substantially identical with those shown in 1g.

The arrangement of Fig. 2, which subdivides the assembly into individual units each including only one vessel, simplifies construction of my device and also facilitates shipment and cleaning thereof as well as replacement of broken or defective parts.

Examples of liquids to be dispensed with my improved apparatus are ninhydrin solutions, analytical Grignard solutions, ferricyanide solutions and hyposulfite solutions. The invention is, of course, not limited to either these particular solutions or the specific constructions described and illustrated but is, on the contrary, capable of numerous modifications and adaptations without departing from the spirit and scope of the appended claims.

I claim:

1. A volumetric dispenser comprising a first chamber having a bottom opening and a top opening, a burette, overflow means connecting said burette with said top opening, a tube connected to said bottom opening, fluid discharge means below said first chamber, valve means for selectively connecting said burette with said tube or with said discharge means, a second chamber above said first chamber, a third chamber above said second chamber, fiuid inlet means at the top of said third chamber, first conduit means connecting the bottom of said third chamber with the bottom of said second chamber, and second conduit means connecting the top of said second chamber with said top opening.

2. A dispenser according to claim 1, wherein said first conduit means comprises a riser tube extending from said third chamber into said second chamber and terminating short of the bottom of the latter.

3. A dispenser according to claim 1, including three superposed vessels of substantially identical volume, each of said vessels enclosing a respective one of said chambers.

4. A dispenser according to claim 1, wherein said first chamber is provided with a filling aperture adjacent said top opening.

5. A dispenser according to claim 1, including a protective liquid in said third chamber, a solution to be dis pensed in said first chamber, and a protective gas in said second chamber, said gas being inert with respect to said so ution.

References Cited in the file of this patent UNITED STATES PATENTS 

